Blackboard-erasing apparatus



Sept. 8, -1925.

W. J. LEARY BLA-CKBOARD ERASING APPARATUS Filed Oct. 26, 1922 4 Sheets-Sheet l .To all, 'it may comer/1L:

Patented Sept. 1925. i l

WILLEM J1. maar; or enreaoo, runners;

Y BLAGK'BOABVHEIASBNG mAMTUS.

immuun una.A (man v26, im; .solo No! 596,961; f Y

Be it lmownitliat L WrLntaM. il. Lnana citizen ofc-,the United Statesiresdillg, effChir cago, .in thecounty of @ook a-nd State of' Illia-ois, han@ new and? useff'uflf provenients in BlackboalgdfErasing ppaifa-tus,v of which theiollowing is a specifi!Y cation. f v

'Phi-s invention relates to, an apparatus or devi-ce1 ilo-r cleaning a blackboard, such asare.

J commonly used-i in schools; and on; which vthe exercises arer Written; by vmeans oii chalk. v

Asis well; known, the clean-ing of; suclr boards is, attended with risks to Vthe health;

oithe teachers.y andscholars, inasmuch as I considerable dust is developed duringk the and'. will operate eicientlqy, without liability cleaning of the boards4 which. is` notonlyl inz-l haled 'by the personsl standing3-knear' the:v board; and; is,l therefore \unsanitafry,y buty is' also objectionable on account of thisdust beingl deposited. onthe clothes ofL the persons andon. the books furnishings; and iiurniture in lthe room. 1 f f Itis the object of this; invention to produce an apparatus forcleaningaor. erasing the' chalk fromsl thegblackboardY in v suchfV a manner that thedust Will `be carried away from the blackboard the instant f the; same iS.- generated, thereby, rendering the: cleaning operation: more. sanitary.y and avoiding. polzi l lutionzof the` atmosphere; f

Y A further object' ofheinirentionis; toil prouidefmeans for accomplishing: this pure:

pose. which can` easily manipulated persons; unskilled; withL mechanical devices;

of getting-fout'of order..

*ii-furrow object or .on invention vis' a 1 provide Van` apparatus off this chanacten vsfhichI cam be produced. at comparati.valgal 10W cost and which caribe inst'alledrsin cleanr rooms: Without. employing expensive' extra equipment.tl f

I'n.. the. aceompanyfingi draawiin'gsi Figure: 1.1l is:s apenspeetiuefview ofthe; coma plete-,blankboard eraser" forming-pant ofthe; cleaningf apparatus: whichz is: constnuctedjin: accordance with. my..v inventions.. Figure; 2; ai vertical longitudinali sectiiuof.' the sama; Figure 3 is a horizontal longitudinal section.

l thereof; takensonsline--3y3aEigc2-- Figure i is-E 'a horizontalf section;` taken onylinef Fig;` 2; looking doumwa-nelly.` Figure-I 5; isf a fragmentary otionalz perspective vieux,` v of' Y' a partition between the; gatheningrf eliminan Figui@ 6- sa horizontal section takenon. f

6%6, 2.1 Figurevrisfa fragmentary seov tionvalperspective `View oft one-endet the lQOSGIling means; of, thev blackboard eraser; Figures 8.- andj9. are verticali tra-ns` versek sections taken on the: conrespolldig'ly i' numbered? lines in lsl`i.g-..v 2. F igure 41-() is, ai horizontal .Section Gallen` on, line 4-l0s-Fga, 2;, looking upwardly; Figure lLluis a iiragf-V mentary bottom-plan View of one end of thev brush.

an *enlarged scale,y oi one portion o-iithe dustloosening Ingeans, showing the manner of attaching a brushf- Strip'1 tO theV suPPQIving; plate orhead., Figure 13 is av fragmentary Fig-11m 12S a vortoial crosssection, i

vertficalI longitudinalsection; taken-` on line lf3- #135: Figi. 121 Y. Figure 14 is;l a fragmentary verticaljtransverse section@ onf anfenlanged l scale',` takenI on line 11i-14,. Fig.` 6.V Figure 15.Y isf afragmentary vsectimaljperspective Offene end? o ,f the bluish;snwing-` w modified :formi offtlie means for attaching' 1the rubbing strips tov the supporting :plate orv head. Figure V1(5ijs a; perspective View?, showing the manner, off installingjono or more eraserson a blackboard in,y accordance ffwithY invention. Figure 17 is afragmentary Vertical longitudinal sect-ion of the,l means mounted; on kthe rail of a ,blackboard for the 'purposevof removing'any accumu-v lated dustonthe blackboard eraser.` Figure fri 18 isa horizontal `section of: the; same taken ony line=1`8--18 Fig;. 1:7` Figures 19.andl areavvertical crosspT sections: taken ony the cor` respondngly numbered@ lines@y in Fig., 16.;l

'Sim-ila!! characters oit-f reterenceV indicate' Views@y f- -v l. Y l The blackboard eraser proper forming part of inyinrpromed apparatus for lcleaning corresponding@ partsV throughout vtl'uef several f blnkboardncomprisesz, dust. loosening;

means-orbrusha `means for-creating a uacuumi. and sucking'ythedusti away from; the;` dust v loosening means; andV a .l,iMld-operated valveA mechanism whereby the suction effect,uponvr the. bnush. may controlled at will;

r The f details'of the: brush' embodying; these features mayf bei variedg, but.the@prefer@rect torn-1:, oif 'bho samel shown in Figs. 144i', is constmcd asffol'lows';

'f (Bhe: dust loosenihgfbnuslipreferably con.

ai reetangulanj border` which; has-l two verse strips connectingopposite;A ends odi the longitudinal strips, and a pluralityr-of longiitueliiial;f intenmediatef 1 32,1 arranged lengthwise within the border, these several strips being constructed of felt or other fibrous material and the same being separated from each other by intervening passages 33 extending from the outer front surface of the same to the rear or inner side of these strips.

These several strips which forni the dust loosening members of the brush, may be supported at their rear or inner edges by a support of 'any suitable construction but preferably by means of a sheet metal supporting plate 34 which latter is secured to the inner edges of these strips and provided with a plurality of slots 35 which correspond with the passages formed between the several strips, so that the dust-laden air which is generated during the operation of cleaning a blackboard may pass through these several passages of the brush from the front to the rear side of the same. 1n the preferred construction of the means for attaching the rear or inner ends of these strips with the metal supporting plate, a longitudinal bead 36 is formed on the strip supportingv plate in rear of each intermediate each of the transverse strips of the border, as best shown in Figs. 1, 6, 8, 9 and 12. Each v of these strips of the brush is provided in its rear side with a longitudinal groove 38 which receives the respective bead, and forms flanges 39 on the inner side of each strip on opposite sides of the respective bead. Each of these flangesjis firmly attached to the adjacent partV of the metal supporting plate by engaging one side of each of these flanges with claws or prongs 40 which are bent out of the stock ofthe adjacent bead and into the respective surface of the -strip flange while the opposite side of this strip flange is engaged by a plurality of prongs or claws 41 which are formed on the adjacent edge of a slot in the supporti-ng plate and engage with the corresponding upright side of the respective flange on one of the strips, as best-shown in Figs. 2, 7, 8, 9 and 1.2-14. A firm hold of the supporting plate is thus obtained upon the several felt strips of the brush which permits of vigorously crubbing the felt strips over the surface of thev blackboard without liability of looseningV the strips. y i

Instead of providing the strip supporting plate with beads which indent the rear surfaces of the strips, as shown in Figs. 2, 7, 9 and 12, this supporting plate may be provided with backwardly-projecting ribs or beads'42, as shown in Fig. 15, which lastmentioned beads. merely serve to stiffen or strengthen this supporting plate without assisting in attaching strips to the supporting plate. j

The brush is mounted on a holder which contains the valve mechanism wherebythe suction through the brush. is controlled, which holder in its preferred forms is constructed as follows: h

43 represents a plate of sheet metal arranged at the back of the brush but separated therefrom by an intermediate gathering chamber or space 44 and also provided with a plurality of openings 45, so that the dust-laden air passing through the several passages between the strips, may enter the gathering chamber and escape through the openings in the plate 43 of the brush holder. This plate 43 is arranged within the flange 46 arranged at theV lower edge of the outer shell 47 of the enclosino casing and is provided with an outwardly-projecting flangey 97 which is secured to the inner vside of the flange 46 of the enclosing casing by brazing. The inner' side of' the brush is spaced apart from the plate 43 by spacingY lugs or projections 4S on t-he marginal parts of the perforated plate 43, so that the same engage the marginal parts of the strip supporting plate, as best shown in Figs. 2, 8 and 9, and thus maintain these plates a predetermined distance apart while they are assembled. The brush is removably held within the flange 47 of the partition or inner wall plate 43 by providing the front end of the latter with an inwardly-turned hook 49 which engages with the shoulder formed by the foremost claws and the front end of the brush, while the shoulder formed by ther claws on the rear transverse edge of the Vbrush is env gaged by means of a catch -50 having a hook-shaped lower end engaging with the last mentioned shoulder while the upper end is pivoted by means of a pin 51 to the rear part of the enclosing casing. This catch is constantly turned by means of a spring 52 in the direction for engaging this hook with the reartransverse'shoulder of the brush, so that the same tends constantly to hold the latter in place. within lthe gathering chamber. Bisengagement of the catch 50 with the rear shoulder of the b-rush may be efl'eoted'by means of a fingerpiece 53 arranged on the outer side of this catch, as shownl in Figs. 1 and 2.' V Y In' order to avoid` marring furniture and parts of the blackboard with which the marginal part of the brush may come in contact, a protecting strip or bumper 54 of rubber or similar material is secured betweenv the inner edge portions of the flange 46 on the enclosing'casingand the adjacent flange 97 of the perforated partition, as best shown in Figs. 2, 8, 9 land 14. l.

In order to draw-the dust-laden air not only through the longitudinal passages -between the strips of the brush, means are provided for also carryingawayany dust which may gather on the outer sides of the border strips,` for which purpose thestrip support.

1,5m, me"

ing piates is provided oni this marginai portion lbetween the outer claws or prongs with a plurality vof notches or recesses 55,*thus forming passages between the marginal l parts ci' the strip supperting platethe inner' side of the flange- 9W on the'r gathering plate tliroug-liwl-iich the airV may pass from.`

the exterior o-f lthe brush alon-gy the outer sides of the outermost strips, into. the dust gathering cllm-mbery andthrouglr the opengatlf'iering piata' ais illustrated 1n casing is arranged a suction' chamber 57 which is adapted to'V bef connected witlran air exhausting device` of any sui-tablevcharac- Yter. rlhis suction chamber and the equalize 2V ing chamber are adapted to beconnected andi' disconnected fromeach other about midway or the lengthof the same by means' of' a passage 58, connecting the ycentralA partsl of these chambersfand a valve 59 which ispreferabl-'y constructed in 'the form- O a plate and adapted to' slide across the central part of this passage. The slide valve is provided with a port 60 adapted tobe moved into and out enregister with thepassage 58.` As

Shown inFig, 23 the yslide-valve 'isl drawn forwardly so that itsy solid or imper-forate part extends across the valve passage, 'thereby disconnecting the suction chamber fromthe.V equalizing chamber and' rendering: the

cleaning action of thea brush-inoperative. Upon moving the slidevalve backwardly until its port 6`Ofisin: register with the' pas-y sage 58,; the suction chamber and equalizing chamber will? beplaced in communication 40' with each other, so thatj the ,suction V effect will causey the dust-laden vairf'to be drawn through the' brush. into the gathering chamber andthrouglil the perforations and equal-ly izing lchamber into the suction chamber; jVv l Y By4 arrangingV this val-ve'passa'ge midway; or substantially so, between the front and rear ends oitheV cleaningl surface of the: brush, the suction -effect wilibe more nearlyA distributed so that all parts offthe 1dust y re? movingarea or the brush will' be actedupon and the dust eiectivelycarried away.l 'In order to still further equalize Vthejrsuc'tionI effect overthe entire area rof2 the rubbing surface of thebrush, those openings of the equal'izing plate. whichL are nearest tothe valve passage 58 are made comparatively smallwhile lthose arranged farther from this' valve passagergare made progressively larger' size, as indicated vap; roXimat'ely in triiution of the. suction `effect is obtained;

overl the entire dust'removin area'of the brush, and cause all parts o` the same vto work-'with substantialiuniformit'y. e The means for' openingand closing the Fifi.' 4, whereby' a substantial/ly uniform dis suction controlling vallve may be varied', but

the sameare preferably soorganized that they may be operated by means of the same hand which manipulates the eraser during' the vcleaning operation by utili-Zing the closing action of the` fingers oiv the operating hand While the same grasps the brush while cleaning the blackboard'.r Forthis purpose, the upper or haiidie` portions-:t the brush is provided on its yopposite l'ongitudinal sides with two valve'operating fingerpieces; 61 61,`

`which are prei'erably-constructedof sheet metal? and ijranged in longitudinalirecesses @Ziormed the adjacent partis of? thetop part or" they sheet metal casing. These vfingerv pieces have their outer edges (connected by means oi' longitudinalhin-ges or pin-tles 63V tol the top part olf the brush handle, sothat the inner parts of thel same'are' capable of moving transversely relativelyl to thehand-l'e-` olf the'lJr-ush.V The inward'inolvement of these fingerpieces towa-rdfeach other' is ejiiectedf bythe pressure of the finge-rs upongrasping the brush, and the' outward movement ofV thefsa'me yis eliecte'd byl means' off resil'ient elements",k asj-willllpr'esent'ly appear.'A This inward motiono-f'V the pieces toward each other isutilized toop'en vthe air valve 59'y and tliexout'ward' motion oi these'A finger pieces servesy tofclosethis valve. The means whereby" the ope-ning ando-losing of the air valve is thus controlled may beconi structed in various ways but: the means for* this" purposeA which areshown in the draw. ings as one suitablefor this 'purpose have ybeen found satisfactory vinf practice 'and thereforepreferred: As there ,'shown, these, means are constructed as follows:k f"

l 64, ire'present two transversely swinging operating levers whicha-re arranged withinl a valve cham-ber 65 ylocated nbetween the front part of` the'V suction chamber and Athe' corresponding part ofthe equalizifng""cha1nber,f these levers being'pivoted'to eachfother'land to the ,adj acent part 'ofy the partition between the suction'. chamberand the' val-veA chamber` by inea-nsf ofa rivet 66 havingiits, axis arat vright angles* to the face of `the; cleaning-:surface of" 'the'b'rush At' their inner 'ends these Naivelevers are pivotally' tendVIH transversely `611mTuffi'thfI-.Ough gui@ p iso the direction for causing their outer ends or arms to approach each other by means of `end against the front arm of one of the valve levers while its outer end engages with a seat 7 3 formed on the adjacent wall of the valve chamber, as best shown in Fig. 3.

In Figs. 2 and 3, the air valve is shown in its closed position which it assumes when the grip upon the finger pieces is released and the cleaner is not in use. l/Vhen it is desired to use the cleaner, the operator upon taking hold of the handle produces an inward pressure of the fingers against both linger pieces which has the effect of pushing the rods 67 inwardly and causing the toggle links to fold toward each other,whereby the valve is caused to move from the front end of the cleaner toward the rear end thereof, asshown in dotted lines in Fig. 8, and move its solid part away from the valve passage and its port 60 into register with said passage, so that now a suction is exerted upon the equalizing and gathering chambers and passages between the cleaning strips for drawing the dust-laden air through the same into the suction chamber. During this inward movement of the finger pieces by the pressure of the ngers of the operator, the springs 72 are compressed, so that upon releasing this pressure against the finger pieces, these springs owing to their resilience, immediat-ely turn the valve levers in the reverse direction and cause the air valve to automatically close.

The suction chamber of the cleaning brush is connected by means of a flexible tube or conduit 7 4 with an air exhausting device of any suitable character, so that the dust which is removed from the blackboard will be carried out of the class room and discharged either to the external atmosphere or into some receptacle provided for that purpose. In orderL to permit of properly manipulating the eraser or cleaner without restraint from the air tube, the latter is connected with the rear end of the cleaner by means of a ball and socket joint which in the preferred formshown in Figs. 1, 2, 3 and 9 comprises a spherical socket 75 arranged at the rear end of the suction chamber and forming av continuation or extension thereof, and a. spherical hollow knuckle 76 which turns in this socket and connects on its inner side therewith while its outer side is provided with a nozzle 7 7 which is connected wit-h the suction line or tube 74.

kIt follows from this construction that the eraser itself may be turned freely into any desired angle with reference to the conduit and thus enables the operator to clean the blackboard without any inconvenience. A packing 78 is preferably interposed between the inner side of the socket and the exterior of the knuckle which serves to prevent any leakage between the same and thus cause the suction effect upon the brush to be most effective for carrying away the dust. In using an eraser of this character o-n a blackboard 79, as shown in Fig. 16, the flexible air conduit which is connected with the brush is preferably extended through a slot or opening 80 in the rail or shelf 81 upon which the eraser ordinarily rests and the fixed end of this tube is connected with a main suction line or pipe 82 which is preferably Varranged underneath this shelf or rail and leads to a vacuum pump or other exhausting device by means of which the air is drawn through the brush and the conduits connected therewith for the purpose of discharging the dust removed by the brush to a space designed to receive the same. In

order to prevent a short kink from being produced in the flexible air tube 7 l nexttothe main suction pipe 82, this part of the fiexible tube is provided with al short section of spring wire 83 which is coiled around the same and fastened to the adjacent fixed part of the main suction line, as shown in Fig. 20. y

In Fig. 16, two of such vacuum erasers are coupled with the same main air exhausting line, the right hand brush being shown in position for use and the left hand brush resting upon theprail when not in use. At a point convenient to bothvof these erasers, the rail of the blackboard is preferably provided with an auxiliarycleaning device with which the faces of the vacuum erasers may be engaged for the purpose of removing any particles of dust which may adhere thereto. The means for this purpose which are shown in Figs. 16, 17, 18 andy 19 are constructed as follows: i

84 represents an auxiliary suction chamber arranged in an opening in the blackboard rail and having its top provided with perforations 85 and with brush bristles 86 while its bottom is connected by means of a branch pipe 87 with the main Aexhaust line..V This branch line contains a valve 88 which may be opened by means of a finger piece 89 guided on the underside of the blackboard rail and connected with a crank 90 on the stem of this valve and adapted to be shifted in a direction for closing this valve by means of a spring 91 interposed between the shifting rod and the adjacent part of the auxiliary suction chamber, las shown .in Figs. 17 and 19. Between the top and bottom of the auxiliary suction chamber is arranged a `distributing plate or equalizer 92 which is perforated and which serves to causethe suction which is created in the lower part of this chamber upon the opening of the valve 88 to be distributed substantially equally over the opening 85 and brush bristles on top of this chamberl so that upon placing the face of one of. the erasers over'the bristles and top openings 'of the auxiliary chamber, ay substantially pressing the hand operated eraser against the bristles of the auxiliary air chamber, this eraser is moved back and forth over the bristles and perforations of the auxiliary chamber, so as to loosen any particles of i dust which may adhere to the vstrips of the eraservand thusA aid in effecting a thorough cleaning of the latter. Y

Thisv blackboard cleaning apparatus 1s 1 very convenientl in use and permits of effectively removing the' dust from the blackboardwith lesseffort than is required in the .usual manner and at thesame time insuring greater comfort for those occupying vthe class room as well as promoting the health of the same and maintaining vthe clothes, books, furnishings and furniture in amore sanitary condition.

Furthermore, this apparatus may be installed at comparatively low cost and without necessitating any material alterations in the structure of the blackboard and other equipment, and without detracting from the appearance of the same. `I claim as my invention:

l. A blackboard cleaner, comprising a plurality of strips of felt which are spaced apart tol form air passages and each of which' is provided on its top with a groove, and a supporting plate of metal having slots registering with said passages, beads engaging with saidgrooves, and claws on the edges of said slots and the walls of said beads and engaging with parts of the strip between the groove therein and the outer sides thereof. f

2. A blackboard I eraser, comprising 'a ing said brush with said holder comprising a fixed hook mounted V.on one end Vof the holder and adapted to engage with the corresponding end of the brush, and a movable catch mounted onthe other'endfof Vthe holder and adapted to engage the same end of the brush.

A blackboard eraser comprising a. holder provided on-its underside with a seat and in its upperpart with a suction chamber, a brush having a support removably seated. in said seat and having a plurality of felt strips and air passages between said strips communicating with said suction "fixed Vhook mounted. on .one end of projections which chamber, means lfor detachably connecting sa1d brush with said holder vcomprising a holderfand adapted toengage with the corresponding end of the brush, a catch pivoted onthe otherV end of the holder and havingl a hook ladapted to engagefthe corresponding endof the brush, and a spring for yieldingly-holding said catch in its operative position. y

said gatheringchamber with said Asuction. chamber, a valve'fo'r controlling the passage between said" gathering Vand suction chambers, and abrush arrangedv below said gathering chamber and provided 'with air. passages communicating rwith said gathering chamberfq,`

part', an equalizingv chamber in its intermediate part which communicates with saidy .suction chamber and has a perforated wall,

and a `brush arranged below said perforated wall and separated therefrom to form a gathering chamber therebetween and having air passages which communicate with said gathering chamber.

6. A blackboard eraser comprising a holder having a suction chamberin its upper part, an equalizing chamber in its intermediate part which communicates lwith said suction chamber and has a perforated wall, and a brush arranged .below said perforated Y 4. IA blackboard eraser comprising a holder having a suction chamber in its upperk part, a gathering chamber in its lower part, `anair passage connecting the central part ofv vmi 5. A blackboard eraser comprisingV a f holder having a suction chamber in its upper wall and separated therefrom to form a gathering chamber therebetween and havlng air passages whlch communlcate wlth said gathermg chamber, the perforatlons 1n said wall being comparatively small adjal cent to the place of communication between saidequalizing chamber and suction chamber and those perforations which are progressively farther from saidplace of communication being of correspondingly larger sizes.

A7. A blackboard eraser comprising a holder having a suction chamber in its upper.

part, an equalizing chamber in its intermediate part which communicates lwith said suction chamber and'has a perforated wall, and a brush arranged below said perforated wall yand separated therefrom to form a gathering chamber therebetween and having air passages which communicate with said gathering chamber, said perforated wall being provided on its underside with are engaged by said brush and which space the latter from said perforated wall.

8. A blackboard holder having an inner perforated wall provided with a marginal depending flange, an

eraser comprising a` outer wall containing a suction chamber i which communicates with said gathering chamber Vand has a depending marginal' flange engaging the flange of said inner wall, a rubber bumper arranged between said flanges, a brush arranged within said Y tween said su-ction chamber and said brush passages, and means for actuating said valve comprising two operating levers pivotally mounted on said holder, springs engaging one end of said levers, shifting rods engaging the other ends of the levers, and means for transmitting the movement of said levers to said valve.

10. A blackboard eraser comprising a holder having a suction chamber, a brush mounted on the holder and having passages communicating with said suction chamber, a slide valve controlling communication between said suction chamber and said brush passages, and means for actuating said valve comprising two operating levers pivotally mounted on said holder, springs engaging one end of said levers, shifting rods engaging the other ends of the levers, and toggle links connecting the other ends o said levers with said slide.

11. A blackboard eraser comprising a holder having a suction chamber, a brush mounted on the holder and having passages communicating with said suction chamber, a. slide valve controlling communication between said suction chamber and said brush passa-ges, and mea-ns for actuating said valve comprising two operating levers pivotally mounted on said holder, springs engaging one end of said levers, shifting rods engaging the other ends of the levers, toggle links connecting the other ends of said levers with said slide, and finger pieces pivotally mounted on opposite sides of said holder and engaging with said shifting rods.

WILLIAM J. LEARY. 

